Go to the bank and take out a bunch of loans that wouldn't be due until after the world ended. Go to the doctor, find out all the ways that I can abuse my body which would be fun now, but where I wouldn't need to suffer any consequences till after the world ended. I have a lot of people to say "I love you" to, and more importantly, all sorts of people to tell off. Finally, I'd find a really cool way to kill myself the day before. I definitely DO NOT want to be around on the day the world ends.
The last day on Earth is probably not going to be a pleasant one. If you're Christian, you have the whole Armageddon thing. Not a fun day, particularly for us who, let's say, haven't been all that observant. Regardless of whether one believes that, presumably if the world is ending there's either a huge war or an environmental catastrophe or whatever. Regardless, most of us will be dying that day. I've never seen six billion people die all at once and don't particularly want to, so I'll be checking out a little early if I get the heads up.
The Earth will most likely survive the next few billion years, but humans will not. I watched a film on TV just this morning about what might happen when the supervolcano beneath the Yellowstone National Park (USA) will erupt and will wipe out all life on the North American continent. People in Europe and Africa are not immune either because they also have similar supervolcanoes, but the one at Yellowstone is the most active.
The Yellowstone Caldera is the largest volcanic system in North America. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released 240 cubic miles (1,000 km³) of ash, rock and pyroclastic materials. This eruption was 1,000 times larger than the 1980 eruption of Mount St. Helens (USA).